Green’s Dictionary of Slang

a room in the King’s Bench prison, London, where prisoners can buy beer.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: The Brace Tavern. a Room in the S.E. corner of the King’s Bench where Beer purchased at the Tap house was retailed at ½ pr Pott advance, for the Convenience of Prisoners residing thereabouts in Bad weather. It was kept by two brothers of the Name of Partridge & thence called the Brace.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn) n.p.: The brace tavern; a room in the S.E. corner of the King’s Bench, where, for the convenience of prisoners residing thereabouts, beer purchased at the tap house was retailed at a halfpenny per pot advance. It was kept by two brothers of the name of Partridge, and thence called the Brace.
1811		Lex. Balatronicum [as cit. 1788].
1860		R. Nicholson Rogue’s Progress (1966) 243: The ‘Brace’ was the next arena of our social diversions.